This invention relates generally to cosmetic containers such as a deodorant stick, and more particularly to a technique for filling a cosmetic container of the push-up type with a cosmetic which initially is in a hot liquefied state and which assumes a solid state at ambient temperature within the container.
A technique according to the invention is applicable to any cosmetic whose constituents are in a molten or liquefied state when heated, the liquid thereafter cooling to assume at ambient temperature a solid or wax-like form. While the invention will be described in conjunction with a deodorant whose constituents have these properties, it is to be understood that the invention is applicable to other cosmetics.
The composition of a typical deodorant stick consists of propylene glycol, sodium stearate, alcohol, fragrance and water. A deodorant stick having these ingredients is usually packaged in a capped container which functions also as an applicator. The container for this purpose is an open-ended cylindrical case within which is received a push-up actuator that normally acts as a piston that rests on an annular lip at the bottom of the case, the actuator serving as a base socket for a column of deodorant material.
The head of the deodorant column projects above the upper end of the case which is threaded to receive a screw-on cap that covers the head. To use the deodorant stick, the cap is unscrewed to expose the head of the column which may now be rubbed onto the underarm region of the user. With continued use, the head is rubbed away until a point is reached where it becomes necessary for the user to push up the actuator at the bottom of the case to an extent creating a fresh head. This procedure is repeated from time to time, the actuator advancing upwardly in steps until the deodorant column is exhausted.
The standard procedure in filling a container case of this type is to place the case in a fixture in an upright position, with the push-up-actuator resting on the bottom lip. The fixture is designcd to form a receptacle at the upper end of the case to avert overflow of the liquefied deodorant onto the threads of the case. The actuator has a cup-like formation whose circular wall formed of resilient plastic material engages the inner surface of the rigid case.
The case in this upright position is then filled through its open top by pouring the deodorant composition therein in its liquefied state. The composition is then permitted to cool and solidify to form a column. Finally, excess material is scraped from the upper end of the column to provide a presentable head, after which the cap is screwed on to seal the package.
A top-filling procedure of the above-described type is a relatively costly and time-consuming operation, not only because it entails the step of placing the case in a fixture but also because it requires a cooling period which must be completed before the column head can be scraped and the cap then screwed onto the case.
There are many advantages to be gained in a bottom-filling procedure for a push-up type container, for then one could do away with the need for a fixture and for a cooling period followed by a scraping step. But while bottom-filling procedures have been carried out with so-called propel-type cosmetic containers, it has not heretofore been possible with push-type containers.
In a propel-type container, a rotatable ring at the bottom of the case is attached to the lower end of a tube coaxially disposed within the case. Threadably received within the tube is a hollow pipe whose upper end terminates in an enlarged circular socket whose side wall engages the wall of the case. The side wall of the socket has a notch therein which rides on a rib extending along the inner surface of the case so that the socket and pipe are free to move axially but not to rotate. Rotation of the ring acts to rotate the tube with respect to the hollow pipe threadably received therein, thereby propelling the socket up and down in the case, depending on the direction of ring rotation.
A propel-type container of this type is filled downside up with liquefied cosmetic which is poured through the tube and the hollow pipe into the case which is enclosed by a removable filling cap. When filling is completed, a sealing plug is snapped into place on the ring. Because the socket which is designed to hold the product is retained by the threads of the propel mechanism, the pressure that must be exerted when snapping in the plug does not displace the socket.
Even though a propel-type container can advantageously be filled from the bottom, it has certain practical drawbacks. The propel mechanism is more complex than the simple actuator in a push-up container and is substantially more expensive to manufacture and assemble. Moreover, the mechanism occupies a significant portion of the case and therefore cuts down the effective capacity of the container. On the other hand, one cannot fill the conventional push-up type container from the bottom; for if the push-up actuator therein were provided with a filling orifice adapted to accommodate a sealing plug, the pressure exerted in snapping the plug in place would advance the push-up actuator and squeeze out the liquefied cosmetic.
If instead of using a snap-in plug to seal the filling orifice one were to drop in a sealing plug in an orientated position and rotate this plug 90.degree. to secure it in place, an adequate seal would not be obtainable. The reason for this is that in a plug that must be rotated to lock it, clearances are required for rotation and this is incompatible with an effective seal when the product, as in the case of a deodorant, has a high alcoholic content and an imperfect seal results in evaporation.